Technique for fabricating integrated incandescent displays

ABSTRACT

Incandescent &#39;&#39;&#39;&#39;microfilaments&#39;&#39;&#39;&#39; for integrated display devices, and the like, are batch fabricated using planar technologies. The planar incandescent filaments are made of thin films, suspended to minimize heat conduction losses. Heat losses are additionally minimized by appropriately shaping the ends of the filaments. By utilizing planar technologies all filaments of a display device may be fabricated en masse in a single plane and, individual filaments may be etched to various shapes and curves thereby obviating the problems encountered where elements must be strung between support posts, in a straight line. Typically, a ceramic substrate is first coated with a layer of reflecting material and etched, if desired, to the pattern selected for the reflecting surface. Thereafter, a support material, such as glass, is deposited over the substrate and reflecting material. Holes are then drilled into the glass and substrate and filled with conductive material, to thereby form support posts. A filament material, such as tungsten, is then deposited over the support layer so as to make conductive contact with the underlying support posts. By using conventional etching techniques a filament of desired pattern is then formed between the posts. Thereafter the support layer may be etched away leaving the filament suspended between the posts.

United States Patent [191 Brown et al.

[ Nov. 5, 1974 TECHNIQUE FOR FABRICATING INTEGRATED INCANDESCENTDISPLAYS [75] Inventors: Alan V. Brown; Frederick Hochberg, both ofYorktown Heights, NY.

[73] Assignee: International Business Machines Corporation, Armonk, NY.

[22] Filed: Oct. 5, 1972 [21] Appl. No.: 296,366

Related US. Application Data [62] Division of Ser. No. 138,409, April29, 1971, Pat.

[52] US. Cl. ..313/49l, 315/64,

[51] Int/Cl. H01j 7/42 [58] Field of Search 313/108 R, 109.5, 275,313/277; 315/64, 66, 68, 69; 340/336 [56] References Cited UNITED STATESPATENTS 3,604,971 9/1971 Tracy 313/1095 Primary Examiner-John KominskiAssistant Examiner-Lawrence J. Dahl Attorney, Agent, or Firm-John A.Jordan [57] ABSTRACT Incandescent microfilaments for integrated displaydevices, and the like, are batch fabricated using planar technologies.The planar incandescent filaments are made of thin films, suspended tominimize heat conduction losses. Heat losses are additionally minimizedby appropriately shaping the ends of the filaments. By utilizing planartechnologies all filaments of a display device may be fabricated enmasse in a single plane and, individual filaments may be etched tovarious shapes and curves thereby obviating the problems encounteredwhere elements must be strung between support posts, in a straight line.Typically, a ceramic substrate is first coated with a layer ofreflecting material and etched, if desired, to the pattern selected forthe reflecting surface. Thereafter, a support material, such as glass,is deposited over the substrate and reflecting material. Holes are thendrilled into the glass and substrate and filled with conductivematerial, to thereby form support posts. A filament material, such astungsten, is then deposited over the support layer so as to makeconductive contact with the underlying support posts. By usingconventional etching techniques a filament of desired pattern is thenformed between the posts. Thereafter the support layer may be etchedaway leaving the filament suspended between the posts.

10 Claims, 23 Drawing Figures PATENIEIJHUV 5 1974 FIG. 1A

FIG. 15

FIG. 1C

FIG. ID

FIG. A

armors 1 I I I I FIG. 1F

FIG. 1G

FIG. IH

FIG. II

am EZ D FIG. IJ

PATENTEDunv 51914 I 3,846,661

- SHEET 3W 3 FIG. 5

FIG. 6

TECHNIQUE FOR FABRICATING INTEGRATED INCANDESCENT DISPLAYS This is adivision of application Ser. No. 138,409 filed Apr. 29, 1971, now U.S.Pat. No. 3,715,785.

BACKGROUND OF THE INVENTION The present invention relates toincandescent illumination and display apparatus, and processes formaking same. More particularly, the present invention relates toimproved incandescent filament arrangements and, processes forfabricating such filament arrangements, particularly as pertains, forexample, to incandescent display devices. In accordance with theprinciples of the present invention planar fabrication techniques areemployed to make improved incandescent elements of a planarmicrofilament variety, which microfilaments" may readily be utilized inintegrated incandescent illumination and display apparatus.

Heretofore, the filaments of incandescent display cells and illuminationapparatus have typically been fabricated by individually wiring eachfilament, of whatever type, to appropriate support posts. One of thedifficulties with such an approach, it can be seen, resides in the factthat it is highly time-consuming and expensive. In addition, such anapproach clearly imposes a restraint upon the size and shape of thefilament that may, practically, be fabricated. One commonly used priorart display apparatus, for example, is manufactured by employing, asindividual incandescent filaments, coiled wire, bonded to posts. It isevident, from such an arrangement that the required bonding process iscumbersome and costly and the fabricated device is limited in size,shape and efficiency.

Not only is the coiled wire filament approach difficult to fabricatebut, in addition, the coiled wire approach, with filament bonded betweensupport posts, necessarily requires the individual filaments to bestretched in a straight-line. Accordingly, individual filament elementscannot be selectively configured to individual shapes. Not only are theindividual filament elements constricted to a straight-line shape but,in addition, when the elements are arranged in a display device,elaborate arrangements must be made to allow the filaments to overlap atthe terminals thereof in order to minimize gaps in the configuredsymbols. This is necessitated, in part at least, by the fact that endlosses, i.e., conduction losses at the filament terminals, prevents theindividual filaments from effectively illuminating the full length ofthe filament wire line. Accordingly, when alphanumeric characters, forexample, are made by the selective illumination of individual filaments,the individual filaments are arranged to overlap at the terminalsthereof so that illuumination is present the full length of the linesegments of the alphanumeric character. such that the character looksrelatively continuous. Exemplary of such an arrangement is thatdescribed more particularly by P. C. Demarest et a]. in U.S. Pat. No.3,408,523, issued Oct. 29, 1968.

It can be seen that in the coiled wire approach to the fabrication ofincandescent filaments, such as that described by Demarest et al.,cumbersome and complex manufacturing procedures are necessarilyencountered. ln addition, it can be seen that display devices fabricatedin accordance with such an approach necessarily are thick, bulky andinefficient, in that the necessity of overlapping the filaments requiresthe filaments to be arranged in different planes. Reduction of thicknessobviously involves critica tolerances and difficult packaging problemswhich significantly effect reliabilny.

It is therefor, accordingly, an object of the present invention toprovide an improved process for the man ufacture of incandescentfilaments.

It is a further object of the present invention to provide an improvedincandescent display device. and improved filament therefor.

lt is still a further object of the present invention to provide animproved incandescent filament for use as an illumination device indisplay cells, and the like.

It is yet a further object of the present invention to provide animproved alphanumeric display apparatus.

It is yet still a further object of the present invention to provide ahighly effective process for fabricating integrated incandescent displayapparatus.

It is another object of the present invention to provide a process forfabricating incandescent display devices where all the filaments of eachdevice are in a single plane and wherein each of the devices may beshaped to any of a variety of selcted configurations.

It is still another object of the present invention to provide anincandescent display device that may be fabricated without the need formechanical assembly.

It is yet still another object of the present invention to provide animproved incandescent display device whereby the incandescent filamentsglow at lower temperatures than heretofore achieved thereby increasingthe lifetime of the filaments. This is accomplished because the planarfilament, in accordance with the present invention, provides a greaterradiating surface area within the character size employed.

It is yet another object of the present invention to provide an improveddisplay device and incandescent filament therefor that may bemanufactured economically and which exhibits high reliability andimproved performance.

Although planar fabrication techniques have, in the past, been appliedto a variety of integrated circuit and semiconductor device constructionprocesses, such techniques have not heretofore been employed in thefabrication of incandescent filaments, as taught in accordance with theprinciples of the present invention.

Typical of the prior art problems confronted with the planar technologyis that involving crossovers in integrated circuits. Exemplary of themanner in which the latter problem is confronted is that given byLepselte'r in the Bell Laboratories Record, in the article entitled NewGold Crossovers Interconnect lntegrated Circuits," February 1968.

In accordance with the principles of the present in vention there isprovided a process for either the individual or batch fabrication ofincandescent microfilaments," using planar technology, whereby displaydevices, and the like, may readily be constructed, en masse withoutmechanical assembly, in a manner so that all the filaments are in asingle plane. The resultant display device so fabricated is economicalin construction costs, simple, reliable and efficient, exhibitingindividual incandescent elements which may be shaped to any of a varietyof desired configurations and which operate at reduced averageillumination temperatures.

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 depicts a series of steps A-J,exemplary of those that may be employed in carrying out the process, inaccordance with the principles of the present invention.

FIG. 2 depicts a perspective view of a typical incandescent filamentconfiguration produced employing the process, in accordance with theprinciples of the present invention.

FIG. 3 depicts a series of steps A-F, exemplary of those that may beemployed to fabricate a channel-type filament form, in accordance withthe principles of the present invention.

FIG. 4 depicts a series of steps A-D, akin to those described in FIG. 1,wherein a channeled substrate is filled to provide a temporary supportand thereafter emptied to leave a free standing filament to bridge thechannel.

FIG. 5 shows a typical l6-segment alphanumeric display cell fabricateden masse in a single process, in accordance with the principles of thepresent invention.

FIG. 6 shows an exemplary 5 X 7 matrix array of incandescent filamentsfabricated en masse, in accordance with the principles of the presentinvention.

DETAILED DESCRIPTION OF THE DRAWINGS In FIG. I is shown a series ofsteps exemplary of those that may be employed in carrying out thepreferred mode, in accordance with the principles of the presentinvention. These steps, designated A-J, depict the significant featuresused in carrying out a process to fabricate a microfilament" typified bythe filament configuration, shown in perspective in FIG. 2.

As shown in step A of FIG. 1, a substrate 1 of ceramic material, forexample, is first coated with a layer 3 of reflective material. In thisregard it should be noted that substrate 1 may be any of a variety ofsupports upon which a reflective material, such as metal, may bedeposited. The layer 3 is to be used as a reflecting surface for theultimate incandescent filament to be fabricated. It should be noted,also, that layer 3 may be deposited by any of a variety of conventionaltechniques, such as vapor deposition or sputtering. Thereafter, layer 3,which may in the typical preferred mode be chromium or tungsten, isetched to the configuration desired for this purpose. As shown in step Bof FIG. 1, this etched configuration may take a form akin to that of theincandescent filament, to ultimately be fabricated. This can be seenmore clearly by reference to FIG. 2 wherein the configuration ofreflector 3 is shown to be the same as incandescent filament 15,thereabove.

After the etching of reflective layer 3, as shown in step B of FIG. 1, asupport layer 5 is deposited thereover, as shown in step C thereof. Thefunction of layer 5 is to support the subsequently applied layer ofincandescent material, to be fabricated into a filament. Typically,layer 5 may be glass, such as Coming 7070 glass. It should be noted herethat although the process described with respect to FIG. 1 depicts asingle incandescent filament, it is clear that these steps are merelyillustrative of the key steps, in accordance with the principles of thepresent invention, and that these steps are likewise applicable to thesimultaneous fabrication of any number of incandescent filaments. Thus,the variously described deposition and etching steps could obviouslyoperate to effect contemporaneous fabrication of any number of variouslyformed filaments. In fact, it is a very significant aspect of thepresent invention that a display cell, employing incandescent filaments,can be fabricated en masse.

After support layer 5, which as hereinabove indicated may be glass, isdeposited upon substrate I with its configured reflective layer 3, asshown in step C, holes are drilled through the glass layer andsubstrate, as shown in step B. These holes may be formed by any of thevariety of techniques. For example, an electron beam drilling techniquemay readily be used. Alternatively, the holes may be machined bymechanical drilling. The holes, as shown at 7 and 9 in step D, are thenfilled with a conductive material to thereby form posts, as shown at 11and 13, in step E. In this regard, the holes may be filled to form postsby an electroplating process, whereby the holes become plated withcopper, for example. It is clear that any of a variety of metals may beemployed to fabricate the posts 11 and I3, as shown in step E. The mainrequirements for these posts are that they are of sufficient strength tosupport the ultimate incandescent filament, to be suspended therebetween, and that they are conductive.

After conductive support posts 11 and 13 have been fabricated, as shownin step E of FIG. 1, a layer of incandescent material 15 is thendeposited upon the layer of glass 5 and into conductive contact with thesupport posts, as shown in step F. Incandescent material 15 may be anyof a variety of well known incandescent materials. In the typicalpreferred embodiment, incandescent layer 15 may be made of tungsten. Theincandescent layer may, it is clear, likewise, be deposited by any of avariety of well known techniques. For example, layer 15 may be depositedby any one of the E-gun evaporation techniques, sputtering techniques orCVD (chemical vapor deposition) techniques. A particular manner in whichselective CVD techniques may be employed to fabricate layer 15 oftungsten will be described hereinafter with respect to FIG. 3.

After incandescent material layer 15 has been depos ited upon supportlay ef iiti setchedto provide the desired filament configuration, asshown by step G of FIG. 1. As hereinabove indicated, FIG. 2 shows onepossible filament configuration. It should be noted, that any of avariety of etching techniques may be employed to etch incandescent layer15 to the desired configuration. For example, conventional photo-resistand chemical etching techniques may readily be employed to appropriatelyetch layer 15. It is clear that utilization of photo-resist techniquesallows the fabrication of very minute and intricate filament patterns.The significance of employing photo-etch techniques will become moreclear hereinafter when it is recognized that very minute individualfilaments are thereby allowed to be fabricated in a matrix array scheme,otherwise not capable of being fabricated using conventional mechanicalfabrication techniques. It should, likewise, be noted that theseconventional photo-etch techniques may also be gmployed to etch thepattern desired in reflective layer After the incandescent filament hasbeen etched, in accordance with step G, a layer of conductive material17 may then be deposited upon the opposing surface 19 of substrate 1,and into conductive contact with support posts 11 and 13, as shown instep H. Thereafter, conductive layer 17 is etched so that all thatremains is a pair of electrical contacts 21 and 23 in respectiveconductive relationship with posts 11 and 13, as shown in step l. Thesecontacts may be in the form of conductive tabs or wire lines. Layer 17may be any of a variety of conductive materials, such as copper. Afterconductive layer 17 has been etched to form electrical contacts 21 and23, as shown in step I, then, support layer 5 is removed as shown instep J. It is clear that support layer 5 may readily be removed by usingprocesses such as chemical etching, or any of a variety of othermaterial removal processes.

FIG. 2 shows a perspective view of a typical incan-:

descent filament configuration, fabricated in accordance with theprinciples of the present invention. It is clear from FIG. 2 thatsubstrate 1 may be any of a variety of ceramic materials, as indicatedwith respect to the description in regard to the steps of FIG. 1.Likewise, filament may be fabricated from any of a variety ofincandescent materials. It should be recognized that the arrangementshown in FIG.

2 is merely illustrative of an arrangement that might be fabricated, inaccordance with the principles of the present invention. Thus, in thisregard, filament 15 may take any of a variety of configurations.

Likewise, substrate 1 may be of any reasonable size and may support asmany filaments as this size will reasonably accommodate. With respect tothe fabrication of multiple filaments on a substrate to create, forexample, a display cell or the likefi t should be recognized that theessentials of the steps enumerated in FIG. 1 remain the same for suchfabrication, as they do for the fabrication of the basic filament showntherein. In particular, the various steps of depositing, etching,removing and the like, remain substantially the same whether a singlefilament is being fabricated or multiple filaments are being fabricated.Thus, it is clear that a display cell may readily be created en masse,using the techniques in accordance with the present invention.

In FIG. 3 there is shown a series of steps A F which may be employed asan alternative to several of the steps shown in FIG. 1. It should berecognized in this regard that the steps shown in FIG. I produce anincandescent filament which is somewhat serpentine in shape in itsplanar dimension. Typically, filament 15 in FIG. 2 may be of the orderof 12 microns wide and l micron thick while being suspended 5 mils abovesubstrate 1. It is clear that smaller widths and thicknesses may befabricated. However, it is likewise clear that the rigidity of thefilament becomes a factor in any practical arrangement. In this latterregard, the steps depicted in FIG. 3 illustrate a process that may beemployed to make the filament channel-shaped to thereby increase itsrigidity.

The initial pre utory steps required in the process depicted in FIG. areakin to those of the process cie= picted in FIG. 1. Accordingly, it canbe seen that step A in FIG. 3 corresponds to step C in FIG. 1, and isarrived at by the same antecedent steps, as those shown at A and B inFIG. 1. Likewise, it can be seen that step B in FIG. 3 corresponds tostep D in FIG. 1. However, after the holes 7 and 9 have been filled soas to create posts 11 and 13, rather than deposit a layer ofincandescent material, as shown in step F of FIG. 1, a layer ofmaterial, which is selectively responsive to the chemical vapordeposition of the incandescent material to be employed, is thereafterdeposited. This selective material is shown as layer 25 in step C ofFIG. 3 and may comprise any of a variety of materials which will act tonucleate the vapor of the incandescent material to be deposited. Thus,where tungsten, for example, is to be employed as the incandesantmaterial and 7070 glass is employed as the support layer 5, then, layer25 may be copper, since copper will nucleate the tungsten vapor while,the 7070 glass will act to oblate the tungsten vapor.

After layer 25, which for purposes of illustration and example may betaken as copper, is deposited on support layer 5, which may be taken as7070 glass, the layer of copper, which is to act somewhat as a mold, isetched to the configuration desired for the ultimate filament to befabricated. As shown in step D of FIG. 3,

After copper layer 25 has been etched to form a mold, the selectivechemical vapor deposition step is then carried out. Accordingly, thearrangement shown in step D is inserted into a chemical vapor depositionchamber whereby it is exposed to a tungsten vapor. In

accordance with such a process the tungsten vapor se lectively depositsupon the copper since the surface of the 7070 glass layer 5 acts tooblate the tungsten vapor, thereby preventing any significant build-upof tungsten thereon. After the desired thickness of tungsten has beendeposited upon the copper, so as to form an incandescent filament 29,the chemical vapor deposition step is terminated and the device isremoved from the chamber. Thereafter, the 7070 glass layer 5 and copperare removed by etching, leaving, in the same manner as described withrespect to the process of FIG. 1, the incandescent filament suspendedbetween posts 11 and 13, as shown in step f. However, it can be seenthat the resultant incandescent filament 29 is channel-shaped and,accordingly, will thereby exhibit added rigidity.

In FIG. 4 there is depicted a series of steps A-D representing a furtheralternative scheme for fabricating incandescent filaments to thatdepicted in FIG. 1. In the arrangement of FIG. 4, rather than employ atemporary support layer, as was done in the previously describedprocesses, a ceramic substrate 31 with a channel 33 may be employed.Channel 33 may be formed by any of a variety of conventional materialremoval techniques, such as, etching. As in the previously describedprocesscs. a pair of holes '7 and 9 are formed in the substrate, asshown in step A. Thereafter, the holes are filled with conductivematerial, as previously described, to create a pair of conductive posts35 and 37. However, as can be seen from the configuration of thesubstrate, these posts are not required to act as sole support for theincandescent filament to be subsequently fabricated. Channel 33 is alsofilled with a material, which is to act as a temporary support. Thismaterial may be any of a variety of materials capable of beingselectively removed thereafter by any of a variety of techniques, suchas,chemical etching. Thus, channel 33 may be filled with a ceramicmaterial, for example, or glass, or metal. Typically, channel 33 may befilled with a metal such as copper, as depicted by 39 in step B of FIG.4.

After channel 33 has been filled, a layer of incandescent material isthen deposited and thereafter etched to form the incandescent filament,as described in the previous processes. This is shown in step C of FIG.4 where incandescent filament 41 is shown exhibiting a shape akintothatdescribed in regzgd to FIGS. 1 and 2. After filament 41 has been etchedthe body of copper 39 in channel 33 may then be removed thereby leavingincandescent filament 41 bridged across the banks of the channel and inconductive contact with posts 35 and 37. It should be recognized thatwhere support layer 5 in FIG. 1 and the support body 39 in FIG. 4 aremade of insulative material, it is not absolutely necessary that they beremoved. However, it is clear that the incandescent filament under suchcircumstances would operate at unnecessarily high power levels.Accordingly, the better mode is to suspend a substantial portion of theincandescent filament in free space whereby heat dissipation may beminimized.

In FIG. 5 there is depicted a conventional 16- segment alphanumericdisplay cell exhibiting incandescent filaments fabricated in accordancewith the principles of the present invention. As can be seen, eachsegment exhibits a zig-zag or somewhat serpentine configuration, akin tothat previously described. It is clear, however, that any of the varietyof segment configurations may be employed. The manner of fabricating the16 segment cell arrangement of FIG. 5 is the same as that described, forexample, in regard to the process of FIG. 1. However, as is evident,rather than directing the process steps toward the fabrication of asingle element, the process steps are to be directed toward fabricatingarrays of segments, en masse. Typically, the cell arrangement of FIG. 5would measure I50 mils high and 100 mils wide. Thus, in fabricating anarrangement as shown in FIG. 5, a ceramic substrate slightly in excessof the dimensions for an array of cells (alphanumeric characters) wouldinitially be chosen. Thereafter a temporary support layer could bedeposited thereupon (not shown) and holes, at appropriate locations,thereafter drilled therethrough'Thus, holes would be drilled byelectron-beam for example, to allow fabrication of posts 43 through 83,as depicted in FIG. 5. After drilling, the holes would be filled and alayer of tungsten, for example, deposited over the entire surface of thesupport layer, as in previously described FIG. 1. Then, the variousfilaments, as depicted in FIG. 5, would be configured by usingphoto-etch techniques and the support layer thereafter removed. It canbe seen that for purposes of illustration the cross-secti0n of thevarious posts is substantially larger than that of the filaments shown.

A l6-segment alphanumeric cell, akin to that depicted in FIG. 5,utilizing a tungsten filament with dimensions of the order of l2 micronswide and 1 micron thick, suspended 5 mils above the substrate by supportposts approximately I00 mils apart, typically operates at a temperatureof l,200 C. Such operating temperatures provide long-life filaments.

In FIG. 6 there is further depicted another example of an incandescentdisplay cell, fabricated in accordance with the principles of thepresent invention. As can be seen, FIG. 6 provides an array ofindividual incandescent filament units 85. The individual filaments,which may be any planar shape, are selectively addressable wherebyselected alphanumeric characters may be created. Typically, thealphanumeric matrix display of FIG. 6 may be a 5 X 7 arrangement,measuring, for example, I50 mils high and I00 mils wide with eachincandescent unit located .025 mils on center. It is clear that with theabove proportions the individual filaments of each unit may be of theorder of 0.015 mils, for example.

It is clear that an incandescent display device comprising a matrixarray of individual incandescent filaments, of the variety anddimensions given above, is not capable of practically being fabricatedby conventional assembly techniques. However, by employing the planaretching techniques of the present invention, such a display cell mayreadily be fabricated en masse.

It should be recognized that although the zigzag or substantiallyserpentine configuration of the planar incandescent filament describedis only one of any of a variety of configurations that may be fabricatedin accordance with the present invention, this particular configurationrepresents a compromise between the strength required to span apost-to-post distance of up to mils and the electrical driving impedancecharacteristic required to match that of the standard logic circuitryemployed in the display driving apparatus. In addition, thisconfiguration provides an efficient and visually pleasing source ofillumination. In this regard it should be noted that since relativelysmall support posts may be fabricated by the present invention,conduction losses at the ends of the filaments are minimized. To improvethis even further it should be recognized that the filaments may befabricated to taper as they approach the posts. Thus, end losses aresubstantially reduced.

It has, likewise, been found that tungsten filaments made in the mannerof the process described with re spect to FIG. 1, exhibit a slight bowupwardly from the surface of substrate 1, as shown in FIG. 2, after thetemporary support layer 5 has been removed. This can be seen to beclearly advantageous when it is recognized that upon energizing thefilament, the filament expands in response to the heat generated.Accordingly, the slight upward bow assures that the filament, uponexpansion, will move away from the surface of substrate 1, therebyavoiding possible contact therewith. In this regard, then, it should benoted that this slight upwardly extending bow may be introduced into theprocess by selecting a material for the temporary support layer whichhas a coefficient of thermal expansion significantly less than that ofthe substrate, such that the combined layers will bow upwardly at thecenter thereof upon cooling, after deposition of the support layer.

While the invention has been particularly shown and described withreference to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the spirit and scope of theinvention.

We claim:

1. An incandescent filament arrangement comprismg:

an insulative substrate base member having a lower surface and an uppersurface and having a plurality of conductive support posts extending atleast from said lower surface through said substrate base member to atleast said upper surface, and a body of incandescent materialcharacterized by being substantially planar in a plane substantiallyparallel to and displaced from at least a portion of said upper surfaceand extending between and being integral with at least two of saidplurality of conductive support posts.

2. The incandescent filament arrangement as set forth in claim 1 whereinsaid body of incandescent material tapers near end of the said at leasttwo conductive support posts so as to compensate for end heat conductionlosses in said incandescent material and cause uniform incandescencealong said body of incandescent material from post to post.

3. The incandescent filament arrangement as set forth in claim 2 whereinthe said support posts which extend to at least the said upper surfaceof said substrate base member project beyond the said upper surface ofsaid substrate base member.

4. The incandescent filament arrangement as set forth in claim 3 whereina layer of reflective material is provided between said body ofincandescent material and said substrate base member.

5. The incandescent filament arrangement as set forth in claim 4 whereinsaid body of incandescent material exhibits over at least a portionthereof a generally serpentine configuration.

6. The incandescent filament arrangement as set forth in claim 5 whereinsaid body of incandescent material is channel-shaped along the path ofsaid serpentine configuration.

7. An integrated incandescent display device comprising:

an insulative substrate base member having a lower surface and an uppersurface and having a plurality of conductive support posts extending atleast from said lower surface through said substrate base member to atleast said upper surface, and a plurality of incandescent filamentsegments for displaying information each of which segment ischaracterized by being substantially planar in a plane substantiallyparallel to and displaced from at least a portion of said upper surfacewith respective ones of said segments extending between and beingintegral with at least two of said plurality of conductive supportposts.

8. The display cell as set forth in claim 7 wherein each of saidfilament segments are of substantially serpentine configuration in saidplane between said posts.

9. The display cell as set forth in claim 8 wherein each of saidfilament segments bows slightly in the direction of view.

10. The display cell as set forth in claim 9wherein said filamentsegments taper in said plane as they approach said posts.

1. An incandescent filament arrangement comprising: an insulativesubstrate base member having a lower surface and an upper surface andhaving a plurality of conductive support posts extending at least fromsaid lower surface through said substrate base member to at least saidupper surface, and a body of incandescent material characterized bybeing substantially planar in a plane substantially parallel to anddisplaced from at least a portion of said upper surface and extendingbetween and being integral with at least two of said plurality ofconductive support posts.
 2. The incandescent filament arrangement asset forth in claim 1 wherein said body of incandescent material tapersnear end of the said at least two conductive support posts so as tocompensate for end heat conduction losses in said incandescent materialand cause uniform incandescence along said body of incandescent materialfrom post to post.
 3. The incandescent filament arrangement as set forthin claim 2 wherein the said support posts which extend to at least thesaid upper surface of said substrate base member project beyond the saidupper surface of said substrate base member.
 4. The incandescentfilament arrangement as set forth in claim 3 wherein a layer ofreflective material is provided between said body of incandescentmaterial and said substrate base member.
 5. The incandescent filamentarrangement as set forth in claim 4 wherein said body of incandescentmaterial exhibits over at least a portion thereof a generally serpentineconfiguration.
 6. The incandescent filament arrangement as set forth inclaim 5 wherein said body of incandescent material is channel-shapedalong the path of said serpentine configuration.
 7. An integratedincandescent display device comprising: an insulative substrate basemember having a lower surface and an upper surface and having aplurality of conductive support posts extending at least from said lowersurface through said substrate base member to at least said uppersurface, and a plurality of incandescent filament segments fordisplaying information each of which segment is characterized by beingsubstantially plaNar in a plane substantially parallel to and displacedfrom at least a portion of said upper surface with respective ones ofsaid segments extending between and being integral with at least two ofsaid plurality of conductive support posts.
 8. The display cell as setforth in claim 7 wherein each of said filament segments are ofsubstantially serpentine configuration in said plane between said posts.9. The display cell as set forth in claim 8 wherein each of saidfilament segments bows slightly in the direction of view.
 10. Thedisplay cell as set forth in claim 9 wherein said filament segmentstaper in said plane as they approach said posts.